Anterior Cruciate Ligament (ACL) Tear: Surgery or Not, Rehabilitation and Return to Sport

Twisted while playing football, caught an edge while skiing or landed awkwardly after a jump, and suddenly your knee gives way: an injury like this is often a tear of the anterior cruciate ligament, known clinically as an ACL rupture. Many people immediately wonder whether they will need surgery. The good news: not every ACL tear needs an operation. Whatever the treatment, targeted rehabilitation is key to a good outcome. At PARAT in Basel, we support you from the first days after your injury through to a safe return to sport.

The anterior cruciate ligament (ACL) is one of the most important stabilising structures in the knee. Inside the joint, it connects the thigh bone to the shin bone and stops the shin bone from sliding forwards. This stabilises the knee during fast movements, changes of direction and landings. It also gives the nervous system feedback about the position of the joint, so it plays an important role in body awareness and in controlling knee movement.

An ACL tear usually happens without direct contact with another person. Typical triggers are sudden changes of direction, abrupt stopping, twisting with the foot planted, or landing after a jump. Sports such as football, handball, floorball, basketball, volleyball and skiing are particularly affected.

Women have a higher risk of ACL injury than men in the same sport. Other risk factors include a previous knee injury, increased joint mobility, excess body weight, muscular imbalances and reduced neuromuscular control, meaning less effective control of movement by the muscles and nervous system.

The knee typically gives way suddenly, often with a “pop” you can hear or feel. Within a few hours, the knee usually swells considerably. Later, it often feels unstable, especially when twisting or changing direction.

Have an injury like this assessed promptly by a doctor or physiotherapist. A clinical examination usually shows whether the ACL is affected. An MRI is mainly useful for detecting associated injuries to the meniscus, cartilage or collateral ligaments.

Not necessarily. In a large randomised trial with young, active adults, structured rehabilitation, with the option of surgery later, achieved results comparable to immediate surgery. Many participants in the rehabilitation group never needed an operation (Frobell et al., 2010). A more recent study found slightly better scores after early surgery at two years, but the difference was small (Reijman et al., 2021).

There is also evidence that, under certain conditions, the ACL can heal. In a study using a special bracing protocol (the Cross Bracing Protocol), in which the knee is held in a bent position for the first few weeks, MRI showed signs of healing after three months in 90% of the 80 participants (Filbay et al., 2023). This approach is still new, is not suitable for everyone and must start very soon after the injury.

Surgery may be advisable if your knee repeatedly gives way in everyday life or during sport despite good rehabilitation, if there are associated injuries such as a locked meniscus, or if you want to return to a sport involving a lot of twisting and stopping. Treatment should always be chosen individually, based on your personal goals, the demands of your sport and the stability of your knee. This decision is best made together with your doctor and us.

With or without surgery, rehabilitation largely determines the outcome. We work in phases. You move on to the next phase once you have reached the goals of the current one, not according to a fixed timetable.

Phase 1 – Swelling and mobility: We reduce the swelling, restore full straightening and bending of the knee and activate the thigh muscles.

Phase 2 – Strength and control: Strength, balance and movement quality are built up step by step.

Phase 3 – Running and jumping: Running training follows, along with jumping and landing training.

Phase 4 – Return to sport: With sport-specific exercises and objective tests, we prepare you to return to training and competition.

Because physiotherapy and personal training are under one roof at PARAT, we support you seamlessly from the first phase of rehabilitation through to performance training.

Prevention remains important even after rehabilitation is complete. Regular strength, balance and coordination training significantly reduces the risk of knee injuries: in studies, prevention programmes halved the risk of ACL injuries in athletes (Webster & Hewett, 2018). Short programmes built into the warm-up two to three times a week have proven effective, such as “FIFA 11+” in football. This kind of training also helps maintain your long-term performance.